1. Field of the Invention
This invention relates generally to a cartridge system for dispensing adhesives, sealants, and similar materials, and more particularly comprising a tubular cartridge gun and a cartridge which is designed to be loaded into the cartridge gun and of which the outlet end projects from the cartridge gun in the loaded position, the cartridge being provided at its outlet end with a receiving spout for attaching a dispensing nozzle.
2. Discussion of Related Art
Known cartridge systems of this type comprise a tubular cartridge gun which, at the outlet end, has a push-through opening for the outlet end of the cartridge. At its outlet end, the cartridge has a receiving spout which is closed at its end and carries an external screwthread. Before a cartridge such as this--preferably made of plastic--is used, the cap-like end of the receiving spout has to be cut off with a knife so that a dispensing nozzle can be screwed onto the cartridge thus opened, and the cartridge thus equipped can be subsequently loaded into the cartridge gun.
A cartridge system of this type is relatively difficult to use because a knife or the like is needed to open the cartridge, but is often not within reach. Another disadvantage is that the cap-like end cut off has to be disposed of or drops uncontrollably onto the floor which is particularly undesirable when this cap-like end is soiled with the contents of the cartridge--something which cannot be ruled out. If the cartridge is filled, for example, with adhesive or a jointing compound, this can have unwanted consequences if, as a result, residues of the adhesive, for example, adhere to the floor.
3. Summary of the Invention
An object of the invention is to improve a cartridge system of the type previously mentioned in such a way that handling of the cartridge system in use would be considerably simplified and, in particular, requires no additional aids is apart from the cartridge system itself.
According to the invention, this and other objects are met by a cartridge system of the type mentioned above wherein the receiving spout is closed internally by a piercable membrane, and the dispensing nozzle is provided at its attachment end with piercing means designed to engage in the receiving spout to pierce the membrane.
By virtue of this design, there is no longer any need to use a knife or the like to open the cartridge, the cartridge is internally closed in the receiving spout by the membrane and can easily be opened quasi-automatically by the attachment of the dispensing nozzle to the receiving spout. The cartridge thus opened and equipped may then be normally loaded into the cartridge gun. Accordingly, when the cartridge is opened, there is no waste which could drop to the floor or would otherwise have to be disposed of.
In one preferred embodiment, the membrane is arranged inside the cartridge at the foot of the receiving spout. This avoids unwanted or accidental damage to the membrane before the cartridge is used because the membrane itself is protected. A protective cap may even be placed on the receiving spout. However, this cap cannot be soiled because the membrane separates the contents of the cartridge from the cap.
Alternatively, the membrane may be arranged in the vicinity of the outlet of the receiving spout.
In one particularly advantageous embodiment, the dispensing nozzle consists of a lower part designed to be fixed to the receiving spout, and an upper part designed for limited longitudinal displacement within the lower part, and which comprises the piercing means on its inner end. The lower part of the dispensing nozzle may thus be fitted or screwed onto the receiving spout of the cartridge with the cartridge still closed and the membrane of the cartridge is automatically pierced by longitudinally displacing the upper part of the nozzle into the lower part, thus releasing the opening of the cartridge. The upper part of the dispensing nozzle may advantageously be displaced after the cartridge has been loaded into the cartridge gun.
In another particularly advantageous embodiment of the invention, in which the handling of such a two-piece dispensing nozzle for opening the cartridge is further simplified, the upper part and lower part of the dispensing nozzle comprise first and second corresponding detent means at a distance apart from one another, the upper part of the nozzle being designed for longitudinal displacement against the effect of the first detent means into the detent position of the second detent means. This embodiment ensures that the two parts of the dispensing nozzle are initially in the first detent position in which the piercing means of the upper part of the nozzle, do not protrude downwards from the lower part of the nozzle and that the upper part of the nozzle is only displaced from the first detent position into the second detent position, in which the piercing means pierce the membrane of the cartridge, after the lower part of the nozzle has been fitted or screwed onto the receiving spout of the cartridge.
In order further to simplify the displacement of the upper part of the nozzle into the lower part, the upper part of the nozzle is externally provided with an encircling stop. This stop may serve as a grip handle.
Another particularly preferred embodiment of the invention is characterized in that the cartridge gun has an outlet end in the form of a pot, which locally surrounds the upper and lower parts of the nozzle and has an opening for the upper part of the nozzle to pass through, the size of this opening being such that, in the loaded position, the upper part of the nozzle comes into contact through its stop with the rim of the outlet opening. This embodiment makes the cartridge system much easier to handle. First, the lower part of the nozzle with the upper part therein is screwed onto the cartridge, after which the cartridge thus equipped is loaded into the cartridge gun, the stop of the upper part of the nozzle coming into contact during loading with the rim of the outlet opening of the pot-shaped outlet end of the cartridge gun, so that by further loading of the cartridge into the cartridge gun or actuation of the trigger lever, which pushes the piston rod and hence the cartridge forward--the upper part of the nozzle is automatically displaced from the first into the second detent position and hence into the lower part of the nozzle through the striking of the stop against the rim of the pot-shaped outlet end of the cartridge gun, whereby the membrane is opened or rather pierced.
In another embodiment of the invention intended, for example, for the modification of normal cartridge guns, the pot-shaped outlet end is made as a separate part designed for insertion into the cartridge gun.
In another particularly advantageous embodiment, a shut-off cock is integrated into the upper part of the nozzle. This shut-off cock is intended to prevent product from issuing from the nozzle after application. In addition, by adjusting the size of the throughflow opening of the shut-off cock, the volumetric flow rate of product can be varied--in addition to the buildup of pressure--at the handle of the cartridge gun.
Above the shut-off cock, there can either be a screwthread on the upper part of the nozzle, onto which a typical commercially available nozzle can be screwed, or the shut-off cock can open directly into the tip of the nozzle.